So I have been asked to teach another nature photography session next weekend. While reviewing the slide show, I noticed that I did not have a good series showing the effects of F-stop. So I ran out to take a few sample shots. Here is the first of two sets - would appreciate your input as to which set of photos you think shows the effect of varied F-stops better. (Also any other suggestions for the class...)

I think the second set is more informative, as you can see the evidence a lot clearer, by looking at the stalk, and the the cobweb on the left. And then on the F32 example, the background is becoming clearer.

This is more visually appealing than looking at cans set at various distances.

The second set of these appears clearer to understand. Although, would you be better off showing an image where more and more of the background is in focus. You see it here if you know what to look for, but someone who doesn't get what you're telling them might not see it.

My photography class I took a few years ago we were to go out and shoot three shots of everything we shot. One at largest f-stop, one mid-stop and one at smallest f-stop with things that were not so close to us as your shots. By the end of the first night we all understood.

IMO, the first series illustrates the background blur (bokeh) and subject isolation better, but the DOF effects on very slight differences in distance of the parts of the subject are more easily seen in the second series. I'd consider both of these points important, so I'd consider showing them both with appropriate explanations.

I think the second set shows more clearly the effect of the f stop on depth of field. If this is an introductory type of course, this may be sufficient. For a more advanced group, the first set might also be included.

I think you can do a better job at demonstrating the DOF. The difference between the f/2.8 and the f/32 is not extreme enough. If they are beginner, I don't think that all of your students will fully understand it.

I think you should add a middle ground in the picture. On your examples, you only have a foreground and background.

As has been pointed out, each has advantages - one for the background and the other for the foreground. If you have to go with one, the second best illustrates the principle. IMO, for background, a more complete range than is shown would be better, with a sharply focused frame to end with and less subtle gradations between increments. Without the short element at the lower left, the second wouldn't work as well, either, for the smaller apertures.

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